U.S. patent number 5,191,230 [Application Number 07/771,154] was granted by the patent office on 1993-03-02 for circuit module fan assembly.
Invention is credited to Lap-Yan Heung.
United States Patent |
5,191,230 |
Heung |
* March 2, 1993 |
Circuit module fan assembly
Abstract
An electronic circuit module fan assembly is disclosed including
a circuit module housing, circuit modules, and a fan module. The
fan module has a fan unit for cooling the circuit modules. The fan
module can be mounted in the housing interchangeably with the
circuit modules. The fan module has time delay circuitry for
delaying the time when the fan module is powered up until after the
initial power surge of the electronic system. The fan module also
has noise filter circuitry. A fan module is disclosed wherein the
fan unit is slidably attached to the fan module to allow the fan to
be placed in different positions for cooling purposes. The fan
module can be constructed so that the fan unit is interchangeable
with a panel having circuitry.
Inventors: |
Heung; Lap-Yan (Hawthorne,
CA) |
[*] Notice: |
The portion of the term of this patent
subsequent to January 7, 2009 has been disclaimed. |
Family
ID: |
26973575 |
Appl.
No.: |
07/771,154 |
Filed: |
October 3, 1991 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
303642 |
Jan 30, 1989 |
5079438 |
|
|
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Current U.S.
Class: |
307/141; 361/23;
361/695 |
Current CPC
Class: |
H05K
7/20172 (20130101); G06F 1/20 (20130101) |
Current International
Class: |
G06F
1/20 (20060101); H05K 7/20 (20060101); H05K
007/20 () |
Field of
Search: |
;307/141,149,150,112
;361/379-415,23-33 ;318/430-434,254 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Ip; Paul
Attorney, Agent or Firm: Sheldon & Mak
Parent Case Text
This is a continuation of the application Ser. No. 303,642 filed
Jan. 30, 1989, U.S. Pat. No. 5,079,438.
Claims
What is claimed is:
1. A fan module for cooling a circuit module in an electronic
system,
wherein the circuit module includes:
(i) a circuit module base board;
(ii) circuitry mounted to the circuit module base board; and
(iii) a circuit module board connector integral with the circuit
module base board;
and wherein the electronic system includes an electrical circuit
and a plurality of receiving connectors each for receiving the
circuit board connector to electrically connect the circuitry to
the electrical circuit in the electronic system and to mechanically
connect the circuit module base board within the electronic
system;
the fan module comprising:
(a) a fan module base board having first and second planar surfaces
and first and second edges;
(b) an electrical fan unit mounted to the first planar surface of
the fan module base board for cooling the circuitry mounted to the
circuit module base board;
(c) a driving circuit electrically connected to the fan unit for
activating the fan unit when the fan module is mounted to the
electronic system and the electronic system is powered on; and
(d) a fan module base board connector integral with the fan module
base board adjacent the first edge for mechanically mounting the
fan module base board to each of the receiving connectors
interchangeably with the circuit module base board and for
electrically connecting the driving circuit to the electrical
circuit through one of the receiving connectors,
the fan unit having a depth such that the fan unit is spaced apart
from the circuitry on the circuit module when the circuit module
and the fan module are mounted to different ones of the receiving
connectors.
2. The fan module of claim 1 wherein (1) the electronic system
further includes a housing, (2) the circuit module further includes
a circuit module bracket assembly attached to the circuit module
base board and attachable to the housing, and (3) the fan module
further includes a fan module bracket assembly attached to the
second edge of the fan module base board and attachable to the
housing interchangeably with the circuit module bracket
assembly.
3. The fan module of claim 1 wherein the fan module base board has
an opening behind the fan unit through which an air flow is
directed when the fan unit is operating.
4. The fan module of claim 1 wherein the driving circuit has a
noise filter for filtering power transients on the driving
circuit.
5. The fan module of claim 1 further including a light-indicator
device for indicating that power for the electronic system is
on.
6. The fan module of claim 1 wherein the fan unit is selectively
mountable on the first and second planar surfaces of the fan module
base board.
7. A fan module for cooling a circuit module in an electronic
system,
wherein the circuit module includes:
(i) a circuit module base board;
(ii) circuitry mounted to the circuit module base board;
(iii) a circuit module board connector integral with the circuit
module base board; and
(iv) a circuit module bracket assembly attached to the circuit
module base board and attachable to a housing of the electronic
system;
and wherein the electronic system includes the housing, an
electrical circuit, and a plurality of receiving connectors each
for receiving the circuit board connector to electrically connect
the circuitry to the electrically circuit in the electronic system
and to mechanically connect the circuit module base board within
the electronic system;
the fan module comprising:
(a) a fan module base board having first and second planar surfaces
and first and second edges;
(b) an electrical fan unit mounted to the first planar surface of
the fan module base board for cooling the circuitry mounted to the
circuit module base board;
(c) a driving circuit electrically connected to the fan unit for
activating the fan unit when the fan module is mounted to the
electronic system and the electronic system is powered on;
(d) a fan module base board connector integral with the fan module
base board adjacent the first edge for mechanically mounting the
fan module base board to each of the receiving connectors
interchangeably with the circuit module base board and for
electrically connecting the driving circuit to the electrical
circuit through one of the receiving connectors; and
(e) a fan module bracket assembly attached to the second edge of
the fan module base board and attachable to the housing,
the fan unit having a depth such that the fan unit is spaced apart
from the circuitry on the circuit module when the circuit module
and the fan module are mounted to different ones of the receiving
connectors.
8. The fan module of claim 7 wherein the fan module base board has
an opening behind the fan unit through which an air flow is
directed when the fan unit is operating.
9. The fan module of claim 7 further including a light-indicator
device for indicating the power for the electronic system is
on.
10. The fan module of claim 7 wherein the receiving connectors
comprise substantially parallel slots in spaced apart relation to
one another and wherein the circuit module board connector and the
fan module board connector each comprise a protruding portion of
the respective base boards, each protruding portion being capable
of fitting snugly in any one of the slots.
11. An electronic system comprising:
(a) a circuit module including:
(i) a circuit module base board;
(ii) circuitry mounted to the circuit module base board; and
(iii) a circuit module board connector integral with the circuit
module base board;
(b) a plurality of receiving connectors each for receiving the
circuit board connector to electrically connect the circuitry to an
electrical circuit in the electronic system and to mechanically
connect the circuit module base board within the electronic
system;
(c) a fan module comprising:
(i) a fan module base board having first and second planar surfaces
and first and second edges;
(ii) an electrical fan unit mounted to the first planar surface of
the fan module base board for cooling the circuitry mounted to the
circuit module base board;
(iii) a driving circuit electrically connected to the fan unit for
activating the fan unit when the fan module is mounted to the
electronic system and the electronic system is powered on; and
(iv) a fan module base board connector integral with the fan module
base board adjacent the first edge for mechanically mounting the
fan module base board to each of the receiving connectors
interchangeably with the circuit module base board and for
electrically connecting the driving circuit to the electrical
circuit in the electronic system through one of the receiving
connectors,
the fan unit having a depth such that the fan unit is spaced apart
from the circuitry on the circuit module when the circuit module
and the fan module are mounted to different ones of the receiving
connectors.
12. The electronic system of claim 11 further including a housing
and wherein (1) the circuit module further includes a circuit
module bracket assembly attached to the circuit module and
detachably attached to the housing, and (2) the fan module further
includes a fan module bracket assembly attached to the second edge
of the fan module base board and detachably attached to the housing
interchangeably with the circuit module bracket assembly.
13. The electronic system of claim 11 wherein the driving circuit
has a noise filter for filtering power transients on the driving
circuit.
14. The electronic system of claim 11 wherein the fan unit is
selectively mountable on the first and second planar surfaces of
the fan module base board.
15. The fan module of claim 1 further including means for reducing
an initial power surge of the electronic system.
16. The fan module of claim 7 further including means for reducing
an initial power surge of the electronic system.
17. The fan module of claim 7 wherein the fan module includes a
plurality of fan units.
18. The fan module of claim 2 wherein the circuit module and fan
module bracket assemblies each comprise (1) upper and lower board
brackets attached to the circuit module and fan module base boards,
and (2) an L-bracket attached to the upper and lower board brackets
and attachable to the housing.
19. The fan module of claim 7 wherein the circuit module and fan
module bracket assemblies each comprise (1) upper and lower board
brackets attached to the circuit module and fan module base boards,
and (2) an L-bracket attached to the upper and lower board brackets
and attachable to the housing.
20. The electronic system of claim 12 wherein the circuit module
and fan module bracket assemblies each comprise (1) upper and lower
board brackets attached to the circuit module and fan module base
boards, and (2) an L-bracket attached to the upper and lower board
brackets and detachably attached to the housing.
Description
BACKGROUND
The field of the present invention is air cooling systems within
electronic systems. More particularly, the present invention
relates to a fan assembly for use in an electronic system with
circuit modules.
Electronic systems, such as computers, employing modular
construction are common. A typical electronic system includes a
plurality of circuit modules mounted within a housing. The circuit
modules can be easily inserted or removed for replacement or
repair. The modular construction contributes to the compactness of
the electronic system.
A plurality of modular integrated circuits or chips are typically
mounted on each circuit module of current electronic systems. As
large scale integration technology has improved, the circuitry per
unit area within a modular integrated circuit has increased
dramatically. The number of modular integrated circuits which can
be packed on a circuit module has also increased. Unfortunately,
this increase in the compactness of electronic circuitry has also
resulted in an increase in the heat generated per unit area of the
circuitry. Therefore, overheating of the numerous chips on circuit
modules has presented a serious problem.
To overcome this problem, most electronic systems employ the use of
air cooling systems in conjunction with heat sink devices.
Typically, air flow from a fan is directed past heat sink devices
which are thermally connected to the circuitry on the circuit
boards. An example of such a device is illustrated in U.S. Pat. No.
4,122,508 to Rumbaugh. In the modular circuit board assembly
disclosed in U.S. Pat. No. 4,122,508, a blower 30 is located in a
side panel of the housing 11. The air flow from the blower 30 is
directed past heat sinks 19 which are thermally connected to
circuit boards 16.
The fan in current electronic systems is usually remote from most
of the circuit modules within the electronic system housing. The
modular integrated circuits on the circuit modules most remote from
the fan receive the least amount of cooling effect because the
cooling air absorbs heat as it passes the circuit modules in closer
proximity to the fan. In many electronic systems, this problem is
exacerbated because the circuit modules which generate the most
heat are often required by the physical constraints of the
electronic system to be located most remote from the fan. As a
result, heat sinks are used to dissipate heat from the integrated
circuits more rapidly than would otherwise be possible. However,
heat sinks decrease the compactness of the electronic system and
increase the cost and complexity of manufacturing the electronic
system.
An additional problem arises from the remoteness of the fan from
many of the circuit modules within the electronic system. Due to
the nature of some system housings, the circuit modules themselves
often block the cooling air flow of the fan from reaching the other
circuit modules.
A further problem is that modular electronic systems typically have
special compartments within the electronic system for housing the
fan, thus contributing to expense in the manufacture of the
electronic system. A further problem resulting from such
compartments is usage of the limited available space within most
electronic systems. The special construction of fan compartments
further increases the difficulty of removing the fan for
maintenance or replacement.
SUMMARY
The present invention solves the foregoing problems. The present
invention is an electronic circuit module fan assembly for an
electronic system which provides more direct air turbulence on the
circuit modules thereby dissipating heat more rapidly and reducing
the need for heat sinks. The present invention also provides a more
compact, a less complex, and a lower cost cooling system.
The electronic circuit module fan assembly of the present invention
comprises at least one circuit module and a fan module within an
electronic system. The assembly can also include a circuit module
housing. The circuit module housing has receiving means for
receivably mounting circuit boards. The circuit module has
circuitry and is mounted on the receiving means of the housing.
The fan module has a mounting structure which can be a base board,
a mounting means for mounting the fan module in the electronic
system, at least one electric fan unit, and a driving circuit which
is electrically connected to the fan unit. The mounting means is
for mounting the fan module in the electronic system
interchangeably with the circuit modules. The electric fan unit is
mounted to the mounting structure so that there is space between
the fan unit and the circuit modules to be cooled when the fan
module is installed in the electronic system. The driving circuit
is for selectively activating the fan unit. The fan unit creates
air turbulence near the circuit module to cool the circuitry of the
circuit module when the driving circuit is activated.
The driving circuit can receive power from the same power source as
the circuit board and can have a time delay means for delaying the
time when the fan unit is activated after the electronic system is
powered on. The driving circuit can further include a noise filter
for filtering power transients. The fan module can have a
mechanical switch for manually selectively activating the fan
unit.
The present invention can also include a light-indicator device for
indicating that the electronic system power is on. The fan module
of the present invention can further be constructed so that the fan
unit is removable and replaceable with modular integrated
circuitry.
The present invention also includes a fan module for an electronic
system. The fan module has essentially the same features as the fan
module of the electronic circuit module fan assembly set forth
above.
DRAWINGS
These and other features, aspects, and advantages of the present
invention will become better understood with reference to the
following description, appended claims, and accompanying drawings
where:
FIG. 1 is a perspective view of an electronic circuit module fan
assembly of the present invention;
FIG. 2 is a front elevation view of a fan module according to the
present invention;
FIG. 3 is a front elevation view of a fan module according to a
second embodiment of the present invention; and
FIG. 4 is a front elevation view of a fan module wherein the fan
unit is removed and replaced with a panel having circuitry.
DESCRIPTION
Referring to FIGS. 1 and 2, an electronic circuit module fan
assembly 10 comprises a circuit module housing 12, circuit modules
14, and a fan module 16. The electronic circuit fan assembly 10 is
part of a larger electronic system, such as a computer system.
Each circuit module 14 comprises a circuit module base board 18, an
array (indicated by the vertical and horizontal double lines 22) of
modular integrated circuits 20, and circuit module mounting means
24 for mounting the circuit module 14 on the side wall 26 of the
housing 12. The modular integrated circuits 20 are mounted in rows
on the base board 18. The side wall 26 functions as a receiving
means for receivably mounting circuit modules 14 and fan modules 16
on the housing 12.
The fan module 16 comprises a fan module mounting structure
including a base board 28. The fan module 16 further comprises a
fan unit 30, fan power wires 32, a driving circuit 34, a
light-indicator circuit 36, and fan module mounting means 38 for
mounting the fan module 16 on the side wall 26. The fan module
mounting means 38 is mounted to the base board 28 by mounting bolts
42. The circuit module mounting means 24 and the fan module
mounting means 38 are of identical construction so the circuit
modules and fan modules are interchangeable. However, the fan
module 16 and the circuit modules 14 can have mounting means of
different construction, as long as the fan module fits into the
same space and mounts to the same receiving means as the circuit
modules 14.
The fan unit 30 is mounted to the fan module base board 28 by fan
bolts 40. Therefore, the fan unit 30 is easily removed from the
base board 28. In some embodiments of the invention, the mounting
structure for the fan unit 30 is not a base board 28. For example,
the mounting structure can be a frame with fan module mounting
means 38 for mounting the frame to the housing 12. Also, a fan
housing can be provided around the fan unit 30 to prevent
interference with electronic signals to or from the electronic
system.
The base board 28 of the fan module 16 can have modular integrated
circuits mounted on the portion of the base board 28 which does not
have the fan unit 30. In addition to modular integrated circuits,
other electronic components, such as components for telephone
communication equipment can be included.
The fan module 28 is electrically connected to the power source of
the electronic system by the board connector 60. The board
connector 60 inserts into the receiving connectors 61 attached to
the housing 12. In some electronic systems, the board connector 60
serves as the fan module mounting means for mounting the base board
28 to the housing 12 because brackets 44, 46, and 48 are not
included. The receiving connectors 61 function as electrical
connections between the board connectors 60 of the modules 14 and
28 and the electronic system. The receiving connectors 61 can also
serve as the mechanical receiving means for receivably mounting the
circuit modules 14 and the fan module 28 on the housing 12.
The mounting means 38 comprises upper and lower board brackets 44
and 46, respectively, and L-bracket 48. The upper and lower board
brackets 44 are attached to the L-bracket 48 by conventional means,
such as rivets or welding. Alternatively, the upper and lower board
brackets 44 and 46 can be adapted to fit into slots within the
L-bracket 48 for easy installation and removal. The L-bracket 48 is
connected to the receiving means by a housing bolt 50. The fan
power wires 32 are connected to the board traces 55 by conventional
electrical connectors.
The fan module 16, and in particular the driving circuit 34,
receives its power from the power source of the electronic system.
The driving circuit 34 has a time delay means for ensuring that the
fan units will not be powered on at the same time as the other
component parts of the electronic system, such as the circuit
modules 14. When the electronic system is powered on, many
component parts of the electronic system draw current from the
system power supply. The time delay means causes the fans to power
up after the initial power surge in the electronic system is over.
For many electronic systems a time delay of approximately one to
two seconds is sufficient.
FIGS. 1 and 2 show only one fan unit 30 mounted on a first planar
surface 54 of the fan module base board 28. However, a second fan
unit could be mounted in the sector 56 on the first planar surface
54. Also, additional fan units could be mounted on the second
planar surface 58 of the base board 28 opposite the first planar
surface 54. The fan units can be mounted at selected positions
along the planar surface of the base board 28. Finally, as is
illustrated in FIG. 4, it is possible to construct the fan module
16 so that the fan unit 30 can be removed and replaced with a panel
92 having modular integrated circuitry, as on the circuit modules
14.
The fan unit 30 has a height and width to fit on the base board 28
without protruding beyond the edges of the base board 28. The depth
or thickness of the fan unit 30 is such that space is left between
the fan module 16 and the circuit modules 14 so cooling air can
flow easily. The fan unit 30 is usually on the planar surface of
the base board 28 opposite to the circuit module to be cooled.
The time delay portion of the driving circuit 34 is illustrated in
FIG. 2. The dotted lines represent electrical traces 55 in the base
board 28. The time delay portion of the driving circuit 34 includes
an input 62 from a 12 V power source of the electronic system, a 1
K ohm resistor 64, a base capacitor 66, an emitter capacitor 68,
and a transistor 70. The 12 V input 62, the 1 K ohm resistor 64,
and the base capacitor 66 are electrically connected in series to
ground 72. The input terminal of the resistor 64 is connected to
the collector of the transistor 70 and the output terminal of the
resistor 64 is connected to the base of the transistor 70. The
emitter of the transistor 70 is connected to the emitter capacitor
68. Both the emitter capacitor 68 and the base capacitor 66 can be
220 .mu.f. The emitter capacitor 68 is connected to ground and thus
can function as a noise filter to filter transients from the power
source of the electronic system.
A mechanical switch 74 is provided so the fan unit 30 can be
manually switched to the on and off states. If a fan unit is
provided in sector 56, a similar mechanical switch can be
provided.
The light-indicator circuit 36 comprises a 5 V input 76 from the
electronic system, a 220 ohm resistor 78, and an indicator light
80, all in series. The indicator light 80 is connected to ground
72. Other light-indicator circuits well known to those skilled in
the art can be provided.
The air flow created by the fan unit 30 during operation is
initially directly through an opening behind the fan unit 30 and
against the adjacent circuit module 14 along the arrow 82. The air
then tends to be directed along the surface of the circuit module
14 away from the area of the fan unit 30. A switch can be provided
on the fan unit 30 so the direction of the air flow can be changed
by changing the rotational direction of the fan blades. In some
embodiments of the invention, channels can be provided between the
circuit modules 14 and the housing 12 so that air can more easily
flow throughout the housing 12. Finally, air vents can be provided
in the housing 12 to take in cool air and let out heated air.
Turning to FIG. 3, another embodiment of fan module 83 is
illustrated wherein the fan unit 30 is slidable on a set of racks
84 and 86. The fan unit is attached to the racks 84 and 86 by
slidable connectors 88. The slidable connectors 88 are attached to
the fan unit 30 by connector bolts 90. The slidable connectors 88
slide along the racks 84 and 86 so that the fan unit 30 can be
positioned at various locations along the opening 89 to cool
circuitry at selected locations on an adjacent circuit module. The
driving circuitry is the same as that of FIG. 2 and can be
electrically connected to the fan unit by fan wires 91 or by other
suitable means well known to those skilled in the art.
FIG. 4 illustrates a fan module 93 on which the fan unit is removed
and replaced with a modular integrated circuit panel 92. The
circuit panel 92 is electrically connected to the electronic system
through the fabric connector 94. In this way, the individual
modular integrated circuits 96 can function in the same way within
the electronic system as they do on a circuit module. The fan
module 93 on which a panel 92 can be mounted is advantageous in
that the module can selectively function as a cooling unit or
mounting structure for circuitry. The driving circuit 34 on the fan
module 93 can be the same as that on the fan module 16 of FIG. 2.
The driving circuit 34 is electrically connected when the circuit
panel 92 is replaced by a fan unit 30.
The electronic circuit module fan assembly of the present invention
has many advantages. The fan module of the present invention can be
located directly adjacent to the circuit module to be cooled. The
present invention provides more direct air turbulence for cooling
of the circuitry than prior cooling systems. The cool air from the
fan unit of the present invention displaces the warming air in
closest proximity to the circuit module. Thereby preventing the
circuit module from getting hot. In prior cooling systems, the fans
are typically located remotely from at least some of the circuit
modules in the electronic system. The proximity of the fan to the
circuit modules can also serve to prevent dust or other particles
from accumulating on the circuit modules or their circuitry.
The electronic circuit module fan assembly of the present invention
also provides a more compact cooling system because a separate
compartment for the fan apparatus is not required. Prior cooling
systems typically locate the fan within a separate cabinet in the
housing, resulting in more complicated and expensive manufacture of
the electronic system and the usage of limited space in the
electronic system. An additional advantage of the present invention
is that the number of fans used in the cooling system can be varied
without major alterations in the electronic system. The fan modules
can be removed or added according to the needs of the user of the
electronic system. If fan modules are removed, there is more room
for additional circuit modules to be installed.
The present invention further provides for ease of removal of the
fan modules for maintenance and replacement. One of the advantages
of electronic systems having circuit modules is ease of maintenance
and replacement of the circuit modules. The present invention takes
advantage of this modular construction in relation to the cooling
system. A further advantage of the present invention is that it can
be easily adapted to draw current from the power source of the
electronic system. Moreover, the close proximity of the fan units
of the present invention to the circuit modules allows for the
employment of fans which draw less power. In prior cooling systems,
the remoteness of the fans from the circuit modules often requires
fans with high capacity air flows. The proximity of the fans to the
circuit modules being cooled also allows for fans with a more
compact size and lower cost and complexity.
Finally, the present invention substantially reduces the need for
bulky and elaborate heat sinks in thermal connection with the
circuitry on the circuit modules. The reason for this is that the
air turbulence provided by the fans of the present invention more
directly cools the circuit modules.
Although various embodiments of the present invention have been
described in considerable detail, other versions and embodiments of
the invention are possible. Therefore, the present invention is not
limited to the embodiments described herein, but instead is defined
by the spirit and scope of the appended claims.
* * * * *